IOLs and production methods for same

ABSTRACT

New intraocular lenses (IOLs) and methods for producing IOLs. The present methods include a combination of steps which increase the pull strength between the fixation member of the IOL and the optic of the IOL without requiring sophisticated high frequency corona discharge activation or plasma activation or other exotic activation of the fixation member or primer coating of the fixation member. The silicone polymeric optic members employed in the present invention can be formed, for example, molded, without recesses to accommodate the fixation members. Such recesses can be formed and provided with a quantity of silicone polymeric material precursor composition after the optic members are produced. The fixation members are then placed in the recesses and secured to the optic members. The present methods are straight forward, easy to practice and are cost effective in producing high quality IOLs.

This is a division of application Ser. No. 08/670,679, filed Jun. 26,1996, now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to intraocular lenses (IOLs) and to methods forproducing IOLs. More particularly, the present invention relates to verystraight forward and easy to practice methods for producing IOLs withoptics comprising silicone polymeric materials and to such IOLs whichhave advantageous properties, for example, outstanding fixation memberpull strengths, that is advantageously large bond strengths between theoptic of the IOL and the fixation member or members of the IOL.

The use of IOLs to improve vision and/or to replace damaged or diseasednatural lenses in human eyes, particularly natural lenses impaired bycataracts, has achieved wide acceptance. Accordingly, a variety of IOLshas been developed for surgical implantation in the posterior oranterior chambers of the eye according to a patient's needs.

Known IOLs comprise an optical lens portion or optic which includes anoptical zone, and one or more, preferably two, supporting structures,called fixation members or haptics, for contacting eye tissue to fix orhold the IOL in the proper position after implantation. The optic maycomprise a soft, resilient material, such as a silicone polymericmaterial (in particular, an elastomeric silicone polymeric material) ora relatively hard or rigid material such as, for example,polymethylmethacrylate (PMMA). The haptics typically comprise a filamentconstructed of a resilient metal or polymeric substance, such as PMMA,polyimide or polypropylene.

Each of the filament haptics is preferably flexible to reduce trauma tosensitive eye structures and to be yielding during insertion of the IOL.In addition, filament haptics generally have a memory retainingcapability, e.g., springiness, so that after implantation of anassociated IOL, the filament haptics automatically tend to return totheir normal orientation.

Although the filament haptics are very useful, certain difficultiesremain. For example, filament haptics and soft or deformable optics tendto be formed from dissimilar materials which do not ordinarilychemically bond together. As a result, filament haptics have beendesigned having a variety of attachment end configurations orstructures, e.g., anchor structures, for providing a physical ormechanical interlock between the haptic and optic. Polypropylenehaptics, for example, have been secured into silicone polymer-basedoptics by means of a mechanical lock. This lock may comprise a smallloop or other anchor formed at the attachment end or lens bonding regionof the haptic, which is then placed in a mold. The precursor material ofthe silicone polymer-based optic is poured into the mold, through and/oraround the lens bonding region of the included haptic or haptics, and isthen cured. Christ et al U.S. Pat. No. 4,790,846 discloses the moldingof an optic around a haptic having a small loop or other anchor toeffect a secure haptic connection.

Christ et al U.S. Pat. No. 4,790,846 further discloses a method formaking an IOL in which a region of an elongated filament haptic has adifferent configuration, e.g., a bulbous enlargement, which cooperateswith the optic of the IOL to form a mechanical interlock between thisdifferent configuration and the optic. If desired, the bulbousenlargement may have its outer surface roughened to improve adhesion ofthe material of the optic.

Blake et al U.S. Pat. No. 5,104,590 discloses improving the adhesiveproperties of polypropylene haptics to silicone lenses through surfacetreatment of the haptic with a combination of a high frequency coronadischarge and a silicone primer. Christ et al U.S. Pat. No. 5,147,397discloses exposing the lens bonding region of the haptic to a plasma atconditions effective to enhance the bondability of the lens bondingregion to the optic. While these procedures can be effective inenhancing haptic/optic bond strength, they are relatively sophisticatedand are relatively expensive to practice, thus adding to the complexityand cost of producing IOLs. In addition, substantial care must beexercised in controlling the corona discharge and plasma exposingprocedures to avoid damaging the relatively fine filament haptics.

Doyle et al U.S. Pat. No. 5,423,929 discloses bonding a fixation memberto an optic of an IOL using a primer component coated on the fixationmember. Using this system, good fixation member optic bond strengths areobtained. However, these methods do involve a step of placing a primercomponent on the fixation member. Also, the presence of the primercomponent or a residue thereof in the eye (with the final IOL) may havesome potential impact on the IOL patient.

It would be advantageous to provide a more straight forward and easy topractice method of producing IOLs which effectively enhances the bond orpull strength between the fixation member or members and the optic.

SUMMARY OF THE INVENTION

New methods for producing IOLs and new IOLs have been discovered. Thepresent production methods are very straight forward, easy to practiceand cost effective, and provide IOLs which have outstanding fixationmember pull strengths. Further, this high or large pull strength isachieved with little or no risk of detrimentally affecting the intrinsicstrength and other advantageous properties of the fixation member inproducing the IOL. It has been found that acceptably large fixationmember pull strengths are achieved, preferably without requiringactivation of the fixation member surface with high frequency coronadischarge or plasma and without coating the fixation member surface withprimer component. The present methods very reliably, predictably andreproducibly produce high quality IOLs.

In addition, since in accordance with the present invention the optic isformed prior to joining the fixation member or members to the optic, theconditions at which the optic is formed can be chosen to optimize theproperties of the optic without consideration for possible damage to therelatively fine filament haptic. Also, relatively low melting pointmaterials of construction can be used in the fixation members. Moreover,the cost of the IOL is reduced, for example, because simplified opticmolding or other optic forming procedures can be employed. Increasedflexibility in molding cycle time and curing temperature, and increasedinterchangeability in the mold tooling required for optic formingresults because the fixation member is not present when the optic isbeing formed. This increased flexibility and interchangeability, inturn, increase production capacity and/or reduce capital and productdevelopment costs.

The present IOLs are straight forward in construction, provide forlittle or no interference with the optical zone of the optic by thefixation member or members and have substantial fixation member/opticpull strengths. The present IOLs are preferably produced using thepresent IOL production methods.

In one broad aspect, the present invention is directed to methods forproducing an IOL including an optic and at least one fixation memberhaving a proximal end or lens bonding region located in the optic. Thepresent methods comprise forming a recess in an optic member, preferablya pre-formed optic member, which comprises a silicone polymericmaterial; placing a precursor composition of a silicone polymericmaterial, preferably a precursor composition of a cross-linked siliconepolymeric material, into the recess; thereafter placing the proximal endportion of the fixation member into the recess; and subjecting the opticmember and the fixation member in the recess to conditions effective topolymerize or cure the precursor composition. The proximal end portionof the fixation member, and preferably the entire fixation member, ispreferably subjected to no high frequency corona discharge or plasmaactivation or other exotic activation procedure, and has no primercomponent coating.

In one particularly useful embodiment, the recess forming step and theprecursor composition placing step occur substantially simultaneously.For example, a hollow needle-like implement is used to puncture theoptic and form the recess. An amount, preferably a controlled amount, ofprecursor composition is passed through the hollow needle-like implementand is placed in the newly formed recess. The amount of precursorcomponent placed in the recess is preferably controlled, more preferablyautomatically controlled, for example, through the use of a precisionmechanism such as a micro stepper motor, a servo motor or a volumetricvalve. Such control enhances the reproducibility (from lens to lens) ofthe present methods and facilitates the production of IOLs having veryconsistent haptic/optic pull strengths in excess of the current ANSIstandard of 50 grams minimum.

The present methods preferably further comprise forming the opticmember, for example, using a mold. The proximal end portion of thefixation member is preferably made of a non-silicon-containing materialand is preferably formed with no anchor structure or structures. In amore preferred embodiment, the fixation member has a length and has asubstantially uniform cross-sectional area along its length. Placing theprecursor composition in the recess prior to the proximal end of afixation member, preferably which has not been subjected to highfrequency corona discharge activation or plasma activation or otherexotic activation procedure and has no primer coating, in combinationwith the other steps of the present methods, has been found to result ina very effective and straight forward approach to producing high qualityIOLs with very advantageous properties.

In another broad aspect of the present invention, IOLs are providedwhich include an optic, and a fixation member, preferably two fixationmembers. The optic member comprises a silicone polymeric material,preferably which is cross-linked. The fixation member includes aproximal end portion or lens bonding region formed with no anchorstructure or structures and secured in the optic. This fixation memberpreferably has been subjected to no high frequency corona dischargeactivation or plasma activation or other exotic activation procedure,and is preferably made of a non-silicon-containing material. No primercomponent or residue thereof is located between the fixation member andthe optic. Such IOLs, which are preferably produced using the presentIOL production methods, have outstanding fixation member/optic pullstrengths.

The invention, together with additional features and advantages thereofmay best be understood by reference to the following description takenin connection with the accompanying illustrative drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified representation of the physiology of the humaneye.

FIG. 2 is a plan view of an IOL in accordance with the presentinvention.

FIG. 3 is a side view of the IOL of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is based, in part, upon the discovery that thefixation member or members of an IOL can be attached or secured to theoptic of the IOL with acceptably high pull strength without requiringmodification to or coating of the surface of the fixation member ormembers. In particular, satisfactory pull strengths or fixation memberor members relative to the optic of an IOL are obtained preferablywithout the fixation member being subjected to high frequency coronadischarge activation or plasma activation and without the fixationmember being coated with a primer material. Because no such surfaceactivation or coating is required, the risk that such activationprocedure or coating will affect the structure and other advantageousproperties of the fixation member or members can be eliminated.

The present methods produce IOLs including an optic, which has anoptical zone through which light passes so that the IOL patient hasimproved vision, and at least one fixation member, preferably twofixation members, having a proximal end portion or lens bonding regionlocated in the optic.

The optic comprises a silicone polymeric material, for example, anelastomeric silicone polymeric material, which is preferablycross-linked. The optic may be, and preferably is, derived from a twopart silicone formulation which is introduced into a mold cavity at aweight ratio of about 1:1, as is known to one of skill in the art. PartA typically includes a catalyst and a base polymer. Part B typicallyincludes a cross-linker and the same base polymer. The base polymer ispreferably synthesized from siloxanes. In one particularly usefulembodiment, the optic comprises a polymer which is a platinum-catalyzed,vinyl/hydride, addition cured poly-organosiloxane. One particularlyuseful optic composition includes a silicone polymeric material which isreinforced, for example, with an effective reinforcing amount of asuitable resin and/or silica. The present optics may include one or moreother components in amounts effective to provide a beneficial propertyto the optic. For example, an effective amount of an ultraviolet lightabsorbing component may be included, preferably covalently bonded to thesilicone polymeric material of the optic.

The present methods of producing IOLs preferably include forming anoptic member. Although other suitable techniques may be employed to formthe optic member, one particularly useful approach is to form aprecursor composition and inject such precursor composition into asuitable mold. The precursor-containing mold is then subjected toeffective conditions, for example, conventional silicone curingconditions, to cure the precursor composition into the desired siliconepolymeric material. The cured material is then removed from the mold andis ready for additional processing in accordance with the presentinvention. Of course, pre-formed optic members can be provided fromother sources and, therefore, the optic member forming need not be partof the present methods.

The optic member is preferably formed with no recess or recesses forinsertion of the fixation member or members. This feature, in which theoptic member as formed includes no recess or recesses for the fixationmember or members, greatly simplifies the procedure by which the opticmember is formed. For example, in the molding approach, the mold doesnot have any additional wires or other means by which recesses for thefixation members are incorporated into the formed optic member. Also,since no such recesses are formed and the fixation member or members arenot included during the optic member forming step, there is no concernwith the fixation member or members at this point in the method. Thus,there is more flexibility in the mold cycle time and curing temperature,and more interchangeability in the mold tooling. This, in turn,increases production capacity and reduces capital, operating and othercosts. Also, since the fixation member or members are not exposed toprolonged curing conditions, a wider variety of fixation membermaterials of construction, for example, including low melting materialsor construction, can be employed.

Each fixation member typically comprises a flexible member comprisingmetal or, preferably, polymeric material, and has a substantiallycircular cross-section, although alternate cross-sectionalconfigurations may be substituted, if desired. The cross-sectional areaof the present fixation members is preferably substantially uniformalong the length of the fixation member or members. The fixation memberspreferably have proximal end portions with no anchor structures. Thefixation members have sufficient strength to provide support for the IOLin the eye. The fixation members may comprise any variety of materialswhich exhibit sufficient supporting strength and resilience and whichare substantially biologically inert in the intended in vivoenvironment. Suitable materials for this purpose include, for example,polymeric materials such as polypropylene, PMMA, polycarbonates,polyamides, polyimides, polyacrylates, polyhydroxyethylmethacrylate,poly (vinylidine fluoride), polytetrafluoroethylene and the like, andmetals such as stainless steel, platinum, titanium, tantalum,shape-memory alloys, e.g., nitonal, and the like. More preferably thefixation member or members comprise a polymeric material, such as thoseselected from polypropylene, PMMA and polyimides, especially extrudedPMMA and polypropylene. The fixation members can be produced usingconventional and well known forming techniques. For example, thepreferred polymeric fixation members can be formed in accordance withknown thermoplastic polymer forming techniques, such as by injectionmolding or by extrusion.

The precursor composition which is placed into the recess or recessesmay be chosen from those conventionally employed in producing siliconepolymeric materials, preferably cross-linked silicone-polymericmaterials, for example, for use in IOLs. In a particularly usefulembodiment, the precursor composition placed into the recess or recesseshas substantially the same chemical make-up or composition as theprecursor composition from which the optic member is formed.

As noted above, the formed optic member preferably does not include anyrecess or recesses into which the fixation member or members can beplaced. In this circumstance, a recess or recesses is separately formedin the pre-formed or already formed optic member. Such recess orrecesses have a size sufficient to accept the proximal end portion ofthe fixation member or members. In one embodiment, the recess formingstep comprises puncturing the optic member with a needle-like implement,and removing the needle-like implement from the optic member. Theneedle-like implement may be coated with the above-noted precursorcomposition before being used to puncture the optic member. This coatingfacilitates the puncturing operation, and may produce a recess having awall at least partially coated with the precursor composition.

A quantity of precursor composition is placed into the recess eitherduring or after the recess forming step.

The recess forming step and the precursor composition placing steppreferably occur substantially simultaneously. In a very effectiveembodiment, a hollow needle-like implement is used to puncture the opticand form the recess while a controlled amount of precursor compositionis passed through the hollow needle-like implement and is placed in therecess.

The amount of precursor composition included in the recess prior toplacing the proximal end portion of the fixation member into the recesspreferably is sufficient to coat a major portion, that is at least about50%, more preferably at least about 70% or about 80% and still morepreferably at least about 95% or substantially all, of the outer surfaceof the fixation member located in the recess. Preferably, excessiveamounts of precursor composition in the recess are avoided since theexcess material may require an additional removal step, either before orafter the precursor composition is subjected to curing or polymerizingconditions. Ideally, the amount of precursor composition placed into therecess is about-equal to the void volume of the recess when the proximalend portion of the fixation member is also located in the recess.

Without wishing to limit the invention to any particular theory ofoperation, it is believed that having a substantial amount of precursorcomposition in the recess before placing the fixation member in therecess allows the precursor composition to be in intimate contact withlarge portions, for example, major portions, of both the inner wall ofthe recess and the outer surface of the fixation member located in therecess. This high degree of intimate contacting facilitates forming astrong bond between the fixation member and the optic as the precursorcomposition in the recess is subjected to curing or polymerizingconditions. In prior systems, the precursor composition was coated onthe fixation member before it was placed in the recess. The act ofplacing this coated fixation member in the recess removed a substantialamount of the precursor so that relatively large portions of the outersurface of the fixation member in the recess could not be effectivelybonded to the optic. The present invention overcomes this problem.

With the fixation member in place in the recess, the optic member andfixation member are subjected to conditions effective to cure orpolymerize the precursor composition located in the recess. Suchconditions are substantially as conventionally used to polymerizeprecursor compositions to form normally solid, preferably elastomeric,silicone polymeric materials. Preferably, such conditions aresubstantially as conventionally used to cure precursor compositions andform cross-linked silicone polymeric materials. Such conditions ofteninclude an elevated temperature, for example, in the range of about 40°C. to about 100° C. or about 150° C. However, the time during which suchcuring or polymerizing takes place is relatively limited because of therelatively limited amount of precursor composition present in therecess. The subjecting step preferably forms an intraocular lensassembly in which the pull strength of the fixation member isacceptable, for example, is increased, preferably by at least about 20%and more preferably by at least about 50%, relative to a similarintraocular lens assembly formed by a similar method in which theprecursor composition is placed directly on the proximal portion of thefixation member and without placing the precursor composition in therecess separate from and prior to placing the fixation member in therecess.

After this subjecting step, the resulting intraocular lens assembly maybe subjected to additional procedures, for example, conventional lensfinishing procedures to produce the final IOL.

An additional important advantage of the present invention is thepredictability and reproducibility of the present methods. Thus, inorder for a method of producing IOLs to be commercially effective, themethod should produce IOLs which have reliably and predictablyreproducible properties, for example, to avoid the production of undueamount of waste materials and to improve cost effectiveness.

The present methods produce IOLs which preferably have fixationmember/optic pull strengths with a standard deviation (defined in aconventional manner) from the mean fixation member/optic pull strengthof a plurality of such IOLs produced in accordance with the presentmethods of less than about 15%, more preferably less than about 10%, ofthe mean pull strength. This outstanding predictability andreproducibility of the present methods lends itself to commercialpractice since the IOLs produced have properties which have acceptablefixation member/optic pull strengths and can be reliably produced whileproducing reduced amount of scrap product.

Without wishing to limit the invention to any particular theory ofoperation, it is believed that the predictability and reproducibility ofthe present methods are directly linked to the straight forward andunsophisticated nature of the present methods. For example, since it ispreferred that no high frequency corona discharge activation or plasmaactivation or primer coating of the fixation member surface be involvedin the present methods, the variability which almost inherently isintroduced because of such activation and coating procedures is notpresent in the present methods. The composition of the optic member, ofthe fixation member, and of the precursor composition placed in therecess, as well as the amount of precursor composition placed in therecess can be very reliably set and controlled. Also, the size of therecess in the formed optic member can be very effectively controlled. Ineffect, each of the steps of the present methods is relatively easy toeffectively control resulting in an intraocular lens assembly which hasreliable, predictable and reproducible properties.

Particularly useful silicone polymeric materials for use as optic membermaterials of construction are reinforced elastomeric compositionsincluding polysiloxane elastomers, preferably having the chemicalcomposition of a cross-linked copolymer including about 12 to about 18mol percent of aryl substituted siloxane units of the formula R₄ R₅--SiO where the aryl substituents (R₄ and R₅ groups) can beindependently selected from phenyl groups, mono-lower alkyl substitutedphenyl groups, and dilower alkyl substituted phenyl groups. Preferably,both aryl groups are simple phenyl, and the resulting diphenyl siloxaneunit is present in the copolymer in an amount of about 14 to about 18mole percent.

The copolymer is end blocked with trisubstituted (monofunctional)siloxane units. At least one substituent of the end blocking groupcontains an olefinic bond. Thus, the general formula of the end blockinggroup incorporated in the copolymer is R₁ R₂ R₃ SiO₀.5 where the natureif the R₁ and R₂ is not critical, and they may be independently selectedfrom, for example, alkyl, aryl, substituted alkyl and substituted arylgroups. R₃ contains an olefinic bond. R₃ is preferably an alkenyl group,more preferably a vinyl group. In a preferred embodiment, the endblocking group is a dimethyl, vinyl siloxane unit. The role of theolefinic (vinyl) group is to enable curing or cross-linking of thepolymer, and preferably covalently linking certain ultraviolet lightabsorbing compounds to the cross-linked copolymer matrix.

The balance of the siloxane building blocks of the copolymer ispreferably dialkyl siloxane units, more preferably with the two alkylsubstituents being ethyl and/or methyl. In other words, the generalformula of the balance of the siloxane building blocks of the copolymeris preferably R₆ R₇ --SiO where the R₆ and R₇ groups are independentlyselected from methyl and ethyl. Preferably both R₆ and R₇ groups aremethyl.

The copolymer may have a degree of polymerization (dp) of about 100 toabout 2000, although a degree of polymerization of about 250 ispreferred, particularly when the R₄ and R₅ groups are phenyl and the R₆and R₇ groups are methyl.

The preparation of the copolymer having the above described componentscan be performed in accordance with processes known in the art, fromstarting materials which are either commercially available or can bemade in accordance with well known processes.

The elastomeric silicone composition preferably contains a reinforcer,for example, a fume silica reinforcer, such as trimethylsilyl treatedsilica reinforcer, finely dispersed therein.

The reinforcer, for example, the fume silica reinforcer, is preferablyused in an amount of about 15 to about 45 parts by weight of thereinforcer to 100 parts of the copolymer. Fume silica itself iscommercially available. The fume silica reinforcer preferably used has asurface area of about 100 to about 450 meter² /gram. More preferably,the fume silica has a surface area of about 200 meter² /gram, is presentin an amount (by weight) of about 27 parts (by weight) to 100 parts (byweight) of the copolymer, and is trimethylsilylated withhexamethyldisilazane substantially in the same step where the copolymeris intimately mixed with the silica.

The intimate mixture of the fume silica with the copolymer is commonlytermed the "base" in the art. For the purpose of making materialssuitable for intraocular lens, the base may be dispersed in a suitableinert solvent, such as trichlorotrifluoroethane, and the dispersionfiltered to remove any solid impurities. Thereafter, the solvent isremoved by gentle heat and vacuum.

In accordance with standard practice in the art, the base is dividedinto two aliquots which preferably are of equal weight. The aliquots arecommonly termed "Part A" and "Part B".

Silicon bonded hydride groups are added to the second aliquot (Part B)in the form of cross-linking agents, which are conventional and wellknown in the art. The liquid organohydrogen polysiloxane cross linkershaving the formula (R)_(a) (H)_(b) SiO_(4-a-b/2) wherein R is simplelower alkyl, for example, methyl, and a ranges from about 1.00 to about2.10 and b ranges from about 0.1 to about 1.0, are eminently suitable.

The platinum catalyst can be selected from materials which areconventional and well known in the art.

The cross-linking should not proceed too rapidly at room temperature,thereby allowing at least two, preferably about six hours for work timewith the mixed aliquots. For this reason, a suitable cross-linkinginhibitor, such a 1, 2, 3, 4 tetramethyl-1,2, 3, 4-tetravinylcyclotetrasiloxane, may be added to the second aliquot (Part B).

Formation of the optic members may be accomplished by liquid injectionmolding, or by cast or compression molding of the intimately mixed PartsA and B. A mixture of Parts A and B, with or without the reinforcercomponent being present is placed in the recess or recesses formed inthe molded optic member.

Referring now to FIG. 1, there is depicted in vivo placement into an eye10 of an IOL 21 according to the present invention, in which a precursorcomposition was included in recesses formed in an already formed opticmember prior to the lens bonding regions of the haptics being insertedinto such recesses.

The cornea 12 serves as a refractory medium in addition to its functionas the anterior wall of the eye 10. The pupil 14 and the iris 15 ofvariable aperture are located behind the cornea 12 and divide the eyeinto an anterior chamber 16 and a posterior chamber 18. The naturalcrystalline lens (not illustrated) is connected by zonular fibers to aperipheral muscle about the lens known as the ciliary muscle 20.

The surgical implantation of IOL 21 is accomplished by an incision inthe eye, removal of the diseased or damaged natural lens (if applicable)and insertion of the IOL into the eye. The optic 26 of IOL 21 includes acentrally located optical zone and may be configured for implantationinto a specific one or either of the anterior or posterior chambers 16or 18. The haptics 28 of IOL 21 extend radially outwardly in the generalplane of the optic 26.

A peripheral limit of anterior chamber angle 22 exists between the baseof the iris 15 and a scleral spur, which serves as a support locationfor IOL 21 implanted within the anterior chamber 16 of the eye 10. Aperipheral zone 23 also exists within the posterior chamber 18 betweenthe ciliary muscle 20 and the base of the iris 15, which is known as theciliary sulcus 24. The peripheral zone 23 serves as a mountain locationfor IOL 21 within the posterior chamber 18. Referring to FIG. 1, IOL 21is shown positioned in the posterior chamber 18 and is supported by thehaptics 28 bearing upon the ciliary sulcus 24.

Referring now to FIGS. 2 and 3, IOL 21 is illustrated as including apair of radially outwardly extending haptics 28 secured to optic 26. Theoptic 26 is made of an optically clear, silica reinforced,platinum-catalyzed, vinyl/hydride addition cured (cross-linked)polyorganosiloxane polymer and has a index of refraction (refractiveindex) of about 1.46. Each haptic 28 has a substantially uniform crosssectional area throughout its length and is shown provided with asmoothly curved region 32, intermediate a lens bonding region 34 and afree end region 36. Although the illustrated embodiment is provided withtwo opposing haptics 28, it is understood that an IOL having only hapticor more than two haptics bonded to the optic by the method disclosedherein is considered within the scope of the invention.

IOL 21 is produced in accordance with the present invention, asdescribed herein. Briefly, the optic 26 is formed, with no recesses toaccommodate the haptics 28, by conventional molding techniques from across-linked silicone polymeric material. If desired, the lens bondingregions 34 of haptics 28 can be mechanically roughened, for example, byabrasion techniques and the like, to facilitate further increasedhaptic/optic bond strengths. Recesses are formed in formed optic 26 toaccommodate the lens bonding regions 34 of haptics 28. Such recesses maybe formed, for example, by puncturing optic 26 to an appropriate depthand at an appropriate location with a needle or a machine tool, such asa drill and the like, or by using photo ablation, ultrasound or a waterjet.

Each of the recesses is formed having a size sufficient to accommodate alens bonding region 34. If a needle is used to form the recesses, it canbe coated with the precursor composition used to form the optic 26.Alternately, a pin coated with the precursor composition can beintroduced into the recess to at least partially coat the walls of therecess with the precursor composition. If desired, the precursorcomposition can be injected into the recess. A quantity of the precursorcomposition used to form the optic 26 is placed in each of the recesses.The recess forming step and precursor composition placing steppreferably occur substantially simultaneously using a hollow needle-likeimplement to puncture the optic and form the recess while passing acontrolled amount of precursor composition through the hollow implementinto the recess. For example, the precursor composition is introducedinto the recess through the hollow implement as the implement is beingwithdrawn from the newly formed recess. The amount of precursorcomposition passed into the recess is preferably controlled using aprecision device, such as a micro stepper motor, a servo motor or avolumetric valve of conventional design.

The lens bonding regions 34 of the haptics 28 are placed in suchrecesses and the entire assembly is subjected to silicone polymer curingconditions to secure the haptic 28 to the optic 26.

The assembled optic 26/haptics 28, which has no primer component orresidue thereof between the optic and the lens bonding regions 34 andhas outstanding haptic/optic pull strength, may be further processed,for example, using one or more conventional lens finishing techniques,and then packaged ready for shipment. IOL 26 may be implanted in the eye10 using conventional techniques. After implantation, IOL 21 functionsvery effectively.

The present methods are very straight forward, easy and inexpensive topractice, and are effective in providing IOLs which have outstandingfixation member/optic pull strengths. Moreover, no exotic activationprocedures and no primer coatings are necessary to prepare the fixationmembers for use in the present IOLs.

While this invention has been described with respect to various specificexamples and embodiments, it is to be understood that the invention isnot limited thereto and that it can be variously practiced within thescope of the following claims.

What is claimed is:
 1. A method of producing an intraocular lensincluding an optic and at least one fixation member having a proximalend portion located in the optic, said method comprising:forming arecess in an optic member which comprises a silicone polymeric material,said recess having a size sufficient to accept the proximal end portionof said fixation member; placing a precursor composition of a siliconepolymeric material into said recess; thereafter placing the proximal endportion of said fixation member into said recess, the proximal endportion of said fixation member being subjected to no high frequencycorona discharge or plasma activation and having no coating thereonprior to being placed into said recess; and subjecting said optic memberand said fixation member in said recess to conditions effective to cureor polymerize said precursor composition and form a combination having apull strength between said fixation member and said optic member inexcess of 50 grams minimum.
 2. The method of claim 1 wherein saidprecursor composition is a precursor composition of a cross-linkedsilicone polymeric material, and said subjecting is effective to curesaid precursor composition.
 3. The method of claim 2 wherein saidsubjecting occurs at an elevated temperature effective to cure saidprecursor composition.
 4. The method of claim 1 wherein said fixationmember is made of a material including no silicon, and said proximal endportion of said fixation member placed into said recess includes noanchor structure.
 5. The method of claim 1 wherein said recess formingstep comprises puncturing said optic member with a needle implement or amachine tool, or employing photo ablation, ultrasound or a water jet. 6.The method of claim 1 wherein said precursor composition placing stepoccurs so as to place a controlled amount of said precursor compositionin said recess.
 7. The method of claim 1 wherein said recess formingstep comprises puncturing said optic member with a hollow needleimplement.
 8. The method of claim 7 wherein said recess forming step andsaid precursor composition placing step occur substantiallysimultaneously.
 9. The method of claim 1 wherein the chemical makeup ofsaid precursor composition is substantially identical to the chemicalmake-up of the precursor composition from which said silicone polymericmaterial included in said optic member is formed.
 10. The method ofclaim 1 wherein said fixation member is made of a material selected fromthe group consisting of polymeric materials and mixtures thereof. 11.The method of claim 1 wherein said subjecting step forms an intraocularlens assembly in which the pull strength of said fixation member isincreased relative to a similar intraocular lens assembly formed by asimilar method in which said precursor composition is placed directly onsaid proximal end portion of said fixation member and without saidprecursor composition placing step.
 12. The method of claim 1 whichfurther comprises roughening said proximal end portion of said fixationmember, said roughening occurring prior to said proximal end portionplacing step.
 13. A method of producing an intraocular lens including anoptic and at least one fixation member having a proximal end portionlocated in the optic, said method comprising:forming a recess in anoptic member which comprises a silicone polymeric material using ahollow needle implement to puncture said optic member and form saidrecess, said recess having a size sufficient to accept the proximal endportion of said fixation member; placing a controlled amount of aprecursor composition of a silicone polymeric material into said recessthrough said hollow needle implement; thereafter placing the proximalend portion of said fixation member into said recess; and subjectingsaid optic member and said fixation member in said recess to conditionseffective to cure or polymerize said precursor composition.
 14. Themethod of claim 13 wherein said recess forming step and said precursorcomposition placing step occur substantially simultaneously.